Tobacco and nicotine use remain critical determinants of health risk in life insurance underwriting. This chapter provides a comprehensive overview of the epidemiology, modalities, and health consequences of tobacco and nicotine consumption, with a focus on implications for insurance medicine. Despite declining prevalence, tobacco use continues to drive preventable morbidity and mortality, particularly through cardiovascular disease, cancer, and respiratory conditions. Emerging products such as e-cigarettes introduce new complexities in risk assessment, especially among younger demographics. It highlights disparities in tobacco use across population subgroups and underscores the importance of targeted interventions and public health policies in reducing usage rates. It also explores underwriting considerations including intensity and duration of use, prior history, misrepresentation, and substandard risk classification. For medical directors and underwriters, understanding these dynamics is essential for accurate risk stratification, premium setting, and claims forecasting.